The present invention relates to an amplifier and in particular to an amplifier for detecting an excessive input at a predetermined level and controlling the attenuation of an input signal.
An amplifier in the related art is designed to prevent clipping caused by an excessive input by attenuating an input signal on detecting that the output potential exceeds a predetermined value, for example, power potential. According to the technique described in JP-A-10-163769, since detection of an output potential alone does not allow reliable determination on the presence of clipping, an input signal is attenuated after occurrence of clipping is surely detected.
The above technique is focused on prevention of clipping. Thus, when clipping occurs or there is a high probability that clipping will occur, the input signal is immediately attenuated. This control triggers attenuation too early and somewhat lacks the feeling of sound volume. Thus, attenuation control of an input signal is in need that prevents excessive distortion caused by an excessive input while maintaining the feeling of sound volume.